scholarly journals Application of Time-Temperature-Humidity Superposition for thePrediction of Wood Properties During Long-Term Ageing

2019 ◽  
Vol 55 (12) ◽  
pp. 427-432
Author(s):  
Eiichi OBATAYA
Keyword(s):  
Wood Properties

Long-term effects of stand density management and genotype on wood properties of loblolly pine (Pinus taeda L.) in the mid-South USA

2021 ◽  
Vol 491 ◽  
pp. 119176
Author(s):  
Michael A. Blazier ◽  
Thomas Hennessey ◽  
Laurence Schimleck ◽  
Scott Abbey ◽  
Ryan Holbrook ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Stand Density ◽  
Wood Properties ◽  
Long Term Effects ◽  
Stand Density Management ◽  
Pinus Taeda L

scholarly journals Changes in the biomass of scots pine (Pinus sylvestris L.) trees in Europe since 1940

2021 ◽  
pp. 6-22
Author(s):  
А.В. Лебедев ◽  
В.В. Кузьмичев
Keyword(s):  
Wood Density ◽  
Scots Pine ◽  
Wood Properties ◽  
Mixed Effect ◽  
Pine Tree ◽  
Mixed Effect Models ◽  
The Face ◽  
Long Term Trends ◽  
Linear Mixed Effect Models

Сосна обыкновенная является одной из основных лесообразующих пород Европы, а ее древесина находит широкое применение в лесопромышленном комплексе. При оценке углерододепонирующих функций считается, что конверсионные коэффициенты являются константными по времени. Последние исследования показывают, что происходящие климатические изменения оказывают существенное влияние на прирост древесины и ее свойства. Цель данного исследования – выявление долговременных тенденций в изменении биомассы фракций деревьев сосны обыкновенной в Европе, происходящих с 1940 г. Для проверки гипотезы о влиянии календарного года на биомассу фракций деревьев проводился регрессионный анализ с применением линейных моделей смешанных эффектов. Проведенный статистический анализ позволил выявить достоверное влияние (при p < 0,05) календарного года только на биомассу стволов в коре. Наиболее сильно изменения проявляются для деревьев в молодняках и средневозрастных насаждениях, где происходит формирование наибольшего радиального прироста. Для крупномерных стволов, согласно результатам моделирования, снижение биомассы стволов в коре не прослеживается. В ближайшие десятилетия в результате продолжающихся климатических изменений процесс снижения биомассы и плотности древесины крупномерных стволов должен усилиться. Выявленные изменения биомассы сопровождаются снижением плотности древесины, что происходит в результате увеличения в структуре годичного прироста более рыхлой и менее плотной ранней древесины. Таким образом, в условиях ускоряющихся темпов роста древесных растений объемы стволов и запасы древесины не должны напрямую пересчитываться в депонированный углерод с учетом исторических значений конверсионных коэффициентов. Это также следует учитывать при мониторинге, моделировании и использовании углерода и биомассы в лесах в условиях глобальных изменений. Scots pine is one of the main forest-forming species in Europe, and its wood is widely used in the timber industry. When evaluating carbon-depositing functions, the conversion rations are assumed to be constant over time. Recent studies show that the ongoing climatic changes have a significant impact on the growth of trees and wood properties. Therefore, the purpose of this study is to identify long-term trends in the change in the biomass of Scots pine tree fractions in Europe since 1940. To test the hypothesis about the influence of the calendar year on the biomass of tree fractions, regression analysis was performed using linear mixed-effect models. The performed statistically analysis made it possible to reveal a significant effect (p < 0.05) of the calendar year only on the biomass of the trunks in the bark. The changes are most pronounced for trees in young and middle-aged stands, where the formation of the greatest radial growth occurs. For large-sized trunks, according to the simulation results, the biomass of the stems in the bark is not traced. In the coming decades, as a result of ongoing climate change, the decline in biomass and wood density of largesized stems should intensify. The revealed changes in biomass are accompanied by a decrease in wood density, which occurs as a result of an increase in the structure of the annual growth of looser and less dense early wood. Thus, in the context of accelerating growth rates of woody plants, the volume of trunks and wood stock should not be directly converted into deposited carbon, considering the historical values of conversion rations. This should also be considered when monitoring, modeling and using carbon and biomass in forests in the face of global change.

scholarly journals Wood properties ofPopulusandBetulain long-term exposure to elevated CO2and O3

2014 ◽  
Vol 37 (6) ◽  
pp. 1452-1463 ◽  
Author(s):  
KATRI KOSTIAINEN ◽  
PEKKA SARANPÄÄ ◽  
SVEN-OLOF LUNDQVIST ◽  
MARK E. KUBISKE ◽  
ELINA VAPAAVUORI
Keyword(s):  
Wood Properties

Long-term development of VOC emissions from OSB after hot-pressing

Holzforschung ◽  
2005 ◽  
Vol 59 (5) ◽  
pp. 519-523 ◽  
Author(s):  
Mathias Makowski ◽  
Martin Ohlmeyer ◽  
Dietrich Meier
Keyword(s):  
Hot Pressing ◽  
Unsaturated Fatty Acids ◽  
Oriented Strand Board ◽  
Wood Properties ◽  
Storage Conditions ◽  
Test Results ◽  
Voc Emissions ◽  
Volatile Organic ◽  
And Storage

Abstract An oriented strand board (OSB) made of Scots pine (Pinus sylvestris L.) was tested for volatile organic compound (VOC) emissions 24 h after the hot-pressing process over a period of 2 months. The predominant emissions from the OSB were monoterpenes and aldehydes. Terpene emissions decreased continuously, whereas aldehyde concentrations initially increased and subsequently decayed. Aldehydes are formed by the autoxidative splitting of unsaturated fatty acids contained in the wood. Due to the delayed release of aldehydes, a comparison of different emission test results is only possible if age and storage conditions are clearly specified. For a reduction in VOC emissions from wood-based materials, wood properties, manufacturing process, and storage conditions have to be considered.

scholarly journals Characterization of Arctic Driftwood as Naturally Modified Material. Part 1: Machinability

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 278
Author(s):  
Daniel Chuchala ◽  
Anna Sandak ◽  
Kazimierz A. Orlowski ◽  
Jakub Sandak ◽  
Olafur Eggertsson ◽  
...  
Keyword(s):  
Cutting Forces ◽  
Sea Water ◽  
Siberian Larch ◽  
Wood Properties ◽  
The Arctic ◽  
Long Term Effects ◽  
Arctic Sea ◽  
Sawing Process ◽  
Natural Modification

Arctic driftwood has reached the coast of Iceland for centuries. This material was used by the inhabitants of the island as a building material for houses, boats, churches and pasture fences. Nowadays, the driftwood is used in the furniture industry, for the finishing of internal and external walls of buildings and also by artists. The properties of driftwood differ to that of original resource due the long-term effects of exposure to Arctic Sea water and ice. This process can be considered as a natural modification, even if its effect on various wood properties and the potential use of driftwood are not yet fully understand. This research is focused on the comparison of cutting forces measured for Siberian larch (Larix sibirica L.) from Siberia provenance and driftwood found on the coast of Iceland. The cutting forces were determined directly from the cutting power signal that was recorded during the frame sawing process. A new procedure for compensation of the late/early wood ratio variation within annual rings is proposed to homogenize mechanical properties of wood. It allows a direct comparison of machinability for both types of larch wood investigated (driftwood and natural). Noticeable differences of normalized cutting force values were noticed for both wood types, which were statistically significant for two set values of feed per tooth. These results provide a new understanding of the effect of the drifting process in the Arctic Sea (natural modification) on mechanical and physical properties of wood. Such a natural modification may influence transformation processes of driftwood as well as performance of the coating systems applied on its surface.

scholarly journals Comparison between growth performance in two silvopastoral systems comprising trees, short-lived perennial shrub, a forage, and livestock)

2021 ◽  
Vol 10 (10) ◽  
pp. e43101018318
Author(s):  
Eduardo Luiz Longui ◽  
Rhayssa Almeida Justo ◽  
Erick Phelipe Amorim ◽  
Adriano Wagner Ballarin ◽  
Miguel Luiz Menezes de Freitas ◽  
...  
Keyword(s):  
Growth Performance ◽  
Physical And Mechanical Properties ◽  
Calorific Value ◽  
Wood Properties ◽  
Production Cycle ◽  
Palm Tree ◽  
Silvopastoral Systems ◽  
Goods And Services ◽  
Perennial Shrub

We aim to determine the growth performance of two 20-year-old silvopastoral systems comprising two timber trees, a palm tree), a short-lived perennial shrub, a forage and livestock; and to investigate fibre features and certain physical and mechanical properties of two timber trees (Myracrodruon urundeuva and Peltophorum dubium) in two plantation systems. The first system is called MP with two timber trees and the second one is called MPS with two timbers and a palm tree. The studied systems showed that it was possible to successfully combine fast-growing species, animals, forage and woody tree species, with a production cycle of more than 50 years of different goods and services (e.g., ornamentals, palm hearts, landscaping, fruits, seeds, bee pasture, meat, and wood). The height, diameter and volume for M. urundeuva trees in the MP system were greater than in the MPS system, whereas no difference between the systems was observed for P. dubium. By comparison, the growth and volume in P. dubium were greater than in M. urundeuva. For wood properties, it was shown that both systems can be used successfully, but the MPS system performed better than the MP system, in the aim of wood production of high mechanical strength and calorific value. In addition, the MPS intercropping system can yield more goods and services than the MP system, both systems bring returns with short-term (bean seed, forage, pasture), medium-term (forage, palm products, pasture, wood), and long-term (wood) financial returns.

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